Power-transmission belt



IVI. I. SMITH.

POWER TRANSMISSION BELT.

APPLICATION FILED OCT. 3, 1919 atented Apr. 5, 1921.

naires ne. i=cs.

MANNING J'. SMITH, OF PHLADELPHEA', PENNSYLVANIA.

rownarnansiuisson BELT.

Specification of Letters Patent.

` ratentea Api'. 5,1921.

Application inea october 3, wie. Vserial no. 328,231.

T 0 @Zlio/1077i, z5/may concern Be it known that l, li/"fiminine d.. SMITH,

a citizen of the UnitedStates, residing at Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a new and useful improvement inPower-Transmission Belts, of which the following is a full, clear, and exact description, reference being had to vthe accompanying drawings, which form a part of this specification.

My invention relates to that kind of end-. less power transmission belt which is formed of a plurality of plies. A known form of such belt comprises two single ply belts see'V cured together in concentric relation, the abutting or overlapping ends of each belt being secured to the other belt by stitching and the two being secured together throughout their length by longitudinal stitching.

Another known form of belt comprises a.V

single belt which is wound upon itself to forma belt of double or triple thickness,

the ends of the belt being secured to an underlying intermediate part of the webbing,

and the several thicknesses being secured` together by stitching throughout the length of the belt.

Belts of the construction described are operative and useful, but possess certain defects causing excessive and rapid wear and tend to become otherwise prematurely impaired. @ne of the most serious defects is the wearing away of the longitudinal stitches, thus destroying or impairing the securing means between the plies of the is used in the fabrication of the ordinary double ply belt and the webbing` Vmay be woven with the same facility; the only element of increased cost being the `slightly increased amountY of labor involved in assembling the elements of the belt, which element of increased cost scarcely affects its sellingprice and is a negligible factor in comparison with the economv resulting from the increased durability of the belt.

kof the belt.

l in unfinished condition.

Fig. 51s a perspective view of the belt A preferredembodiment of myinvention is shown in the accompanying drawings,y in whichc p Figure l is an edge view of the belt partly broken away with the final joint"V in unfinished condition.' i

Fig. 2 is a plan view. of a belt ywith kthe joint nished.

Fig. 3 is a cross-section through one reach portion of the Fig. t is an edge View of the inner flat webbing of the belt, the joint being shown of Fig. l. n c

Fig. 6 is a perspective view of one of the ends of the outery tubular webbing.

I i'irst weave` an'ordinary flat webbing a ofa length slightly exceeding the intended circumferential length-fof lthe belt. l then weave a tubular webbing or cover Z), also of a length slightly exceeding the intendedl circumferential lengthfof the belt. The tubular webbing contains the same number of warp threadsfan'd weft threads as the fiatl webbing; but instead of all the warp threads interl'acing with all the weft threads, half Lthe warp threads interweave with half the weft threads in an upper shed of the loom, while theremaining warp threads and weft threads interweave with the remaining weft threads in lower shed ofthe loom. manner of so weaving a tubular'fabric is known in the art and need not be further and specifically described.

It will beunderstood, from the above exy planation, that the combined thickness of the two belts is the same as that of two ordinary flat webs.

The flat webbing is then inserted within" the tubular webbing or cover and is passed through the same until both webbings about coincide. The extremities of the tubular webbing are then pushed back and the ex-.

tremities of the flat vwebbing are then manner. A preferred way of securing together the extremities of the flat-webbing is to rfray the ends, preferably by removing the weft, bring the v.two extremities ofthe solid part of the webbing together so that they about coincide and secure the kfrayedout warp ends c, c, togthe lunderlying and adjacent solid parts of the webbing by suitable stitching. Alternatively, the frayed sections may be secured together in order that the thickness of the webbing will not The `abutted and secured together in any known be increased at the joint due to the removal of the weft. 1

The flat webbing has now been formed into an endless belt. rlhis belt is `now worked along longitudinally within the cover so that its united ends will be at a greater or less distance from the vopposing ends of the tubularwebbing or cover Z).

The opposing ends of the cover are now `secured together. Preferably, I proceed as follows. Before theinsertion of the `flat webbing each end of the tube is frayed' vthroughout half its transverse circumference, the inner half of the tube being frayed at one end and the outer half of the tube at the other end. VThe ends of the solid part of the tube are then brought into substantially coinciding relation That is, the extremity of one end of the solid outer half of thetube is brought opposite the .other extremity of the solid outer half of the tube, and the extremity of one solid end of the inner half of the tube is brought opposite the other extremity of the solid inner half of the tube. This leaves frayed end d to be secured to the adjacent solid part.of the outside of the tube and a frayed end e to be secured to the adjacent solid part of the inside of the tube.

rihe .tubular cover Z) is now secured to the belt a by longitudinal lines of stitches f.

lt has been found in practice that even though the longitudinal stitches on the inside of the compound belt may wear away, the two elements of the belt are still held in fixed relation by the outside longitudinal stitches f and the driving quality and du* rability of the belt will not beimpaired. Again, in case of the wearing upon either edge of the belt, it is necessary to wear throughthe edge of the tubular belt before the selvage edge of the inner flat webbing can be attacked and it is necessary to also wear away this selvage edge before any fraying in possibly occur. Again, the tendency to stretch is practically eliminated, because although the outside ply of the belt may tend to stretch, it is restrained `from l doing so by its integral association with the inside ply of the belt.

lt is obvious that if it is desired to make a belt of triple thickness, either the inside belt may be prepared of double thickness, or the tubular belt may be woven through? out of the saine thickness as the flat webbing, instead of being woven ofl half the thickness, as above described.

Having now fully described my invention, whatl claim and desire to protect byV .Letters Patent is:

l. An endless compound power transf mission belt comprising an inner lat web` bing and an inclosing tubular webbing, the ends of the fiat webbing being secured together and positioned between the ends of the tubular webbing and the ends of the tubular webbing being secured together ,and positioned between the ends of the flat comprising inner flat webbing and an` inclosing tubular webbing, the latter at one end being cut away across its inner transn verse semi-circumference and frayed across its youter' transverse semi-circumference and at the other end being cut away across its outer 'transverse semi-circumference and frayed across its inner transverse semi-circumference, the two frayed extremities being secured Vto opposing solid faces of the tubular webbing.

4i. An endless compoundlpower transmission belt comprising an inner flat webbing of given thickness, and an inclosing tubular webbing having approximately the same yardage and weight of yarn and of a transverse circumference approximating twice the width of the flat webbing, the ends of the fiat webbing` being secured together between the ends of thetubular webbing and the ends Vof the tubular webbing being secured together, thereby forming a compound belt having a thickness approximating' that of two flat webbings of the given thickness specified.

5. rin endless compound power transmission belt comprising an inner `Slat webbing of1` given thickness, and an inclosing tubular webbing having approximately the same yardage and weight of yarn and of a circumference approximating twice the width of the fiat webbing, the ends of the flat webbing being frayed out and secured together and the ends of the-tubular webbing being frayed out semi-circumfei'entially and secured together, thereby forming a compound belt having a thickness approximat-A ing that of two flat webbings of the given thickness specified.

in testimony of which invention, I have hereunto set my hand, at Philadelphia, Pa., on this lst day of Uctober, 1919.

. MANNING J. SMlTl-I.

iooV 

